22 
Psyche 
[March 
order was a later development than the Mecoptera, I be- 
lieve that the Upper Permian specimens demonstrate that 
the Neuroptera are at least as old a group as the Mecop- 
tera. The finding of true Odonata in the Lower Permian 
was one of the surprising discoveries of the decade; pre- 
viously no Odonata had been known from the Paleozoic, 
but subsequent to the finding of the Lower Permian fossils, 
an Upper Permian species has also been located. All these 
described Permian forms possessed petiolate wings, more 
narrow and elongate than any recent types. As in the case 
of the Mecoptera, the Permian Odonata were very small, 
some having a wing-expanse of about 4.0 cm. The absence 
of Odonata with broad wings basally from the Permian has 
lead Tillyard to the conclusion that the Anisoptera and the 
Anisozygoptera were derived from the petiolate Zygoptera 
during the Triassic. For my own part, I do not accept this 
inference, but consider that both the anisopterous and 
zygopterous lines were already developed during the close 
of the Upper Carboniferous. The occurrence of true Ilomop- 
tera in the Lower Permian is of much significance, espe- 
cially since we are forced to admit that they appear to be 
the most highly specialized of all the insects of this horizon. 
Numerous Homoptera, even more highly developed, have 
been taken in the Upper Permian of Australia and Russia. 
The finding of Psocids in the Lower Permian was perhaps 
the most surprising discovery made in the field of fossil 
insects for many years. At the time when these fossils were 
collected, the earliest record of the order was in the Baltic 
amber, of Tertiary age, some 200 million years later, but 
subsequent to the finding of the Permian specimens, Marty- 
nov has taken others in the Jurassic of Turkestan. The 
Permian Psocids were very similar in venation to the Ho- 
moptera, and were nearly as highly specialized. The Plec- 
toptera or Ephemerida have long been recognized as very 
primitive insects, so their presence in Lower Permian beds 
is not at all surprising. The Permian species, although more 
primitive than any recent forms, were nevertheless well 
developed along certain lines and show that the order 
originated far in the past. The other Permian orders, the 
Diptera, Orthoptera, and Coleoptera, are too sparsely rep- 
resented in our collections just now to enable us to form any 
definite idea as to how far they had developed along their 
